The purpose of this paper was to assess primary school teachers’ mathematical problem solving ability. The researchers employed case study research design to examine their mathematical problem solving ability. This paper presents the analysis of the responses of a case study, named Suria (a pseudonym), related to a particular task, Fencing problem. Finding of the study suggests that Suria has successfully solved the fencing problem using trial-and-error (also known as guess-and-check) strategy. She used alternative strategy, namely differentiation method, to check the answer for the fencing problem without being probed. The implication of the finding was also discussed.

Keywords: primary school teachers, mathematical problem solving ability, case study.